Note: Descriptions are shown in the official language in which they were submitted.
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SUPPORT STRUCTURE
Field of the Invention
This invention relates to a support structure for underground water storage
and,
more particularly, to a support structure for providing internal support
within an
underground stormwater storage system.
Background of the Invention
It is known to provide a series of stacked plastic modules to form an
underground
structure for storage of stormwater. One such module of this kind forms the
subject of
Australian Patent No. 724,847. The plastic module disclosed in this document
is able to be
stacked with other like modules to form a structure having a volume which is
mainly
empty space (ie. 94% void) capable of being filled with water. At the same
time, the
structure is strong enough to support an overlying ground surface which, in
turn, can
support, specifically, legally fully loaded transport vehicles.
However, the applicant has identified that the above module is relatively
costly to
manufacture, and is also over-engineered for some applications.
Examples of the present invention seek to provide an improved support
structure
for underground storage of water.
Summary of the Invention
In accordance with one aspect of the present invention, there is provided a
support
structure for providing internal vertical support within an underground water
storage
system, including a column member, a foot spreader module adapted for fitting
to a lower.
end of the column member to support the column member in a substantially
vertical
orientation on an underlying surface, and a head spreader module adapted for
fitting to an
upper end of the column member to support an overlying surface relative to
said
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underlying surface, whereby the column member with said foot and head spreader
modules
fitted thereto forms a column support for supporting a ground surface above
the water
storage system.
Preferably, the head spreader module and the foot spreader module are like
units,
with the unit of the head spreader module being inverted relative to the foot
spreader
module when fitted.
Preferably, the spreader modules are generally tapered outwardly to distribute
load
from the column member over an area greater than a cross-sectional area of the
column
member.
Preferably, the spreader modules are provided with reinforcing ribs or the
like.
Preferably, the column member has reinforcing ribs or the like.
In accordance with another aspect of the present invention, there is provided
a unit
for forming the foot and head spreader modules of the support structure
described above,
wherein the unit includes a seat portion adapted for seating with the
underlying and
overlying surfaces, and a coupling portion adapted for fitting to the column
member,
wherein the unit has ribs extending outwardly from the coupling portion to the
seat portion
for distributing load from the column member.
Preferably, the unit is integrally formed as a single piece. More preferably,
the unit
is formed of plastic. Even more preferably, the unit is formed of
polypropylene.
Alternatively, the unit is formed of polyethylene terephthalate (PET).
In accordance with another aspect of the present invention, there is provided
a
method of forming a support structure for providing internal vertical support
within an
underground water storage system, including the steps of:
providing a column member;
fitting an outwardly tapered foot spreader module to a lower end of the
column member to distribute load from the column member to an underlying
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surface beneath the foot spreader module across a load transfer area greater
than a
cross-sectional area of the column member; and
fitting an outwardly tapered head spreader module to an upper end of the
column member to distribute support from the column member to an overlying
surface above the head spreader module across a load transfer area greater
than a
cross-sectional area of the column member,
whereby the column member with said foot and head spreader modules
fitted thereto forms a column support for supporting a ground surface above
the
water storage system.
Preferably, the method further includes the step of cutting the column member
to a
length to suit site-specific criteria.
Preferably, the method further includes the step of securing the foot spreader
module to a lower unit forming the underlying surface. More preferably, the
method
further includes the step of securing the head spreader module to an upper
unit forming the
overlying surface. Even more preferably, the securing is achieved by way of a
clip having
a barbed end for connecting to an aperture in the spreader module, and a
hooked end for
hooking around an element of the upper and/or lower unit.
In accordance with another aspect of the present invention, there is provided
a
support system including at least one support structure as described above,
adjacent at least
one support unit, wherein the support unit is capable of supporting load and
has a void
capable of being filled with water.
Preferably, the support unit is formed of a plurality of modular layer units.
More
preferably, the support system includes a three-dimensional grid formation
having an
outside perimeter region formed of a plurality of support units laid in side-
by-side
arrangement and an inner region within the outside perimeter region formed of
a plurality
of support structures laid in a side-by-side arrangement.
More preferably, the support system includes an upper layer formed of the
modular
layer units on top of the three-dimensional grid formation, and a lower layer
formed of the
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modular layer units below the three-dimensional grid formation. Even more
preferably,
the upper and lower layers are arranged such that each of the support units
has above and
blow an additional modular layer unit, and each of the support structures has
above and
below a modular layer unit forming said overlying and underlying surfaces.
More preferably still, the support system includes a further upper layer on
top of said
upper layer, the further upper layer including modular layer units
horizontally offset
relative to the modular layer units of said upper layer. Similarly, preferably
the support
system includes a further lower layer below said lower layer, the further
lower layer
including modular layer units horizontally offset relative to the modular
layer units of
said lower layer. The support system may include one or more additional layers
of
modular layer units above the further upper layer and/or below the further
lower layer.
In accordance with another aspect of the present invention, there is provided
a support
structure for providing internal vertical support within an underground water
storage
system, comprising: a column member; a foot spreader module adapted for
fitting to a
lower end of the column member to support the column member in a substantially
vertical
orientation on an underlying surface; and a head spreader module adapted for
fitting to an
upper end of the column member to support an overlying surface relative to
said
underlying surface, whereby the column member with said foot and head spreader
modules fitted thereto forms a column support for supporting a ground surface
above the
water storage system, wherein the head spreader module and the foot spreader
module are
each formed of a modular unit common to both spreader modules, and the column
member is a load bearing member which vertically supports the head spreader
module in
spaced relationship to the foot spreader module, and wherein the modular unit
is tapered
outwardly to distribute load from the column member over an area greater than
a cross-
sectional area of the column member.
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In accordance with another aspect of the present invention, there is provided
a method of
forming a support structure for providing internal vertical support within an
underground
water storage system, comprising the steps of: providing a column member;
forming an
outwardly tapered head spreader module and an outwardly tapered foot spreader
module,
each being formed of a modular unit common to both spreader modules; fitting
the
outwardly tapered foot spreader module to a lower end of the column member to
distribute
load from the column member to an underlying surface beneath the foot spreader
module
across a load transfer area greater than a cross-sectional area of the column
member; and
fitting the outwardly tapered head spreader module to an upper end of the
column member
to distribute support from the column member to an overlying surface above the
head
spreader module across a load transfer area greater than a cross-sectional
area of the
column member, whereby the column member with said foot and head spreader
modules fitted thereto forms a column support for supporting a ground surface
above the
water storage system, the column member being a load bearing member which
vertically
supports the head spreader module in a spaced relationship to the foot
spreader module.
Brief Description of the Drawings
The invention is described, by way of non-limiting example only, with
reference to
the accompanying drawings in which:
Figure 1 is a diagrammatic side view of a support structure in accordance with
an
example of the present invention;
Figure 2 is a diagrammatic side view of the support structure of Figure 1,
shown in
an arrangement amongst layers of stormwater storage layer modules of an
existing type;
Figure 3 is a diagrammatic perspective view of a support system for
underground
water storage including a plurality of support structures of the kind shown in
Figures 1 and
2;
Figure 4 is a diagrammatic perspective view of a column member and a foot
spreader module of the support structure shown in Figures 1 and 2;
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Figure 5 is a perspective view of a spreader module in accordance with another
example of the present invention;
Figure 6 is an underside detailed view showing part of the spreader module of
Figure 5 supported on a stormwater storage layer module;
Figure 7 is a top view of the arrangement shown in Figure 6;
Figure 8 is a diagrammatic perspective view showing a pair of clips for
securing a
spreader module to a stormwater storage layer module; and
Figure 9 is a detailed perspective view showing a pair of stormwater storage
layer
modules coupled with a clip.
Detailed Description
With reference to Figure 1, a support structure 10 is provided for internal
vertical
support within an underground water storage system. The support structure 10
includes a
column member 12, a foot spreader module 14 and a head spreader module 16. The
foot
spreader module 14 is adapted for fitting to a lower end 18 of the column
member 12 to
support the column member 12 in a substantially vertical orientation on an
underlying
surface 20. The head spreader module 16 is adapted for fitting to an upper end
22 of the
column member 12 to support an overlying surface 24 relative to the underlying
surface
20. The column member 12 with the foot and head spreader modules 14, 16 fitted
thereto
forms a column support for supporting a ground surface above the water storage
system,
such that, for example, roads, car parks, sporting fields, parks and some
small building
structures can be supported above the water storage system.
The head spreader module 16 and the foot spreader module 14 are like units 42,
with the unit 42 of the head spreader module 16 being inverted relative to the
foot spreader
module 14 when fitted. The head and foot spreader modules 16, 14 are generally
tapered
outwardly to distribute load from the column member 12 over an area greater
than a cross-
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sectional area of the column member 12. Accordingly, the spreader modules 16,
14
increase the stability and load carrying capacity of the column member 12
which may be
formed from a plastic pipe by cutting the plastic pipe to length to suit site-
specific criteria.
In one particular example, the pipe used is 300mm diameter PVC stormwater pipe
having
12mm wall thickness. In an alternative example, the column member 12 may have
reinforcing ribs such as, for example, radially spaced internal fin-like ribs
running along
the length of the member 12 to further increase its load carrying capacity and
lateral
stability.
Figure 3 shows diagrammatically a support system 28 including a plurality of
support structures 10 arranged together in a 3x4 grid-like inner region within
a perimeter
region of support units 30. The support units 30 are arranged in a side-by-
side 5x6
formation to surround the grid-like formation of the support structures 10.
Each of the
support units 30 is capable of supporting load and has a void capable of being
filled with
water, and may be in the form of a stack of modular stormwater storage layer
units 32 of
an existing kind, such as the kind referred to as "Rainstore3" disclosed in AU
724847, or
any other suitable storage layer unit which may be of the kind disclosed in US
7,080,480.
As the support structures 30 use less material than the support units 10, the
support
system 28 shown in Figure 3 uses less material and has a greater capacity for
storing water
than if it were formed with only support units 10.
A support system 28 formed in accordance with the example shown in Figure 3
may also include an upper layer 34 formed of like modular layer units 32
arranged on top
of the perimeter and inner regions, and a lower layer 36 formed of like
modular layer units
32 below the perimeter and inner regions (see Figure 2). The upper and lower
layers 34,
36 are arranged such that each of the support units 30 has above and below an
additional
modular layer unit 32, and each of the support structures 10 has above and
below a
modular layer unit 32 forming said overlying and underlying surfaces 24, 20.
The support system 28 may also include a further upper layer 38 on top of the
upper layer 34, the further upper layer 38 including like modular layer units
32
horizontally offset relative to the modular layer units 32 of the upper layer
34, so as to
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increase strength of the support system. Similarly, the support system 28 may
also include
a further lower layer 40 below the lower layer 36, the further lower layer 40
including like
modular layer units 32 horizontally offset relative to the modular layer units
32 of the
lower layer 36. The offsetting of the modular layer units 32 of the further
upper layer 38
and the further lower layer 40 may be half the side length of a singular
modular layer unit
32, and may be in both orthogonal directions within the plane of the layers
38, 40. In one
particular example, the modular layer units 32 are 1000mm x 1000mm x 1 Omm,
and the
offset is 500mm.
Yet a further layer 41 of modular layer units 32 may be provided above and
connected to the further upper layer 38 by means of multiple joining plastic
pipe sleeves
32a of the modular layer units 32 (see Figure 1). Each modular layer unit 32
also has a
frame 32b which interconnects the pipe sleeves 32a of that unit 32. The
modular layer
units 32 of the upper layer 34 may be oriented such that the plastic pipe
sleeves 32a of
those units 32 extend downwardly from the frames 32b of the modular layer
units 32; the
modular layer units 32 of the further upper layer 38 may be oriented such that
the plastic
pipe sleeves 32a of those units 32 extend upwardly from the frames 32b of the
modular
layer units 32, and modular layer units 32 of the further layer 41 may be
oriented such that
the plastic pipe sleeves 32a of those units 32 extend downwardly from the
frames 32b of
the modular layer units 32. In this way a suitable surface for walking on
during installation
of the support system 28 is provided by the frames 32b of the modular layer
units 32 of the
further layer 41.
Referring now to the support structure 10 in more detail, the head and foot
spreader
modules 16, 14 may be formed, for example, by using a unit 42 having a square
base as
shown in Figure 4, or by using a unit 42 having a round base as shown in
Figure 5.
The unit 42 of Figure 5 includes a substantially planar circular seat portion
44
adapted for seating on the underlying surface 20 and overlying surface 24, and
a coupling
portion 46 adapted for fitting to the column member 12. The coupling portion
46 is in the
form of a sleeve sized to fit around an end of the column member 12, and has a
rim for
abutting against an end of the column member 12. The unit 42 has ribs 48
extending
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outwardly from the coupling portion 46 to the seat portion 44 for distributing
load from the
column member 12.
The unit may be integrally formed as a single piece, injection moulded in
plastic.
The type of plastic used may be, for example, polypropylene or polyethylene
terephthalate
(PET). Polypropylene has the advantages of being easy to mould, strong and
readily
available. PET has the advantages of being highly rigid, very strong and even
more readily
available than polypropylene, but it is more difficult to work with.
Mounting of the support structure 10 relative to the neighbouring storage
layer unit
32 may include securing the foot spreader module 14 to a lower storage layer
unit 32
forming the underlying surface 20, and securing the head spreader module 16 to
an upper
storage layer unit 32 forming the overlying surface 24. The parts may be
secured at
locations where ribs 52 of the spreader modules 14, 16 are aligned with an
adjacent
framework 54 of the frame 32b of the adjacent storage layer unit 32. Examples
of such
locations are identified by reference numeral 50 in Figures 6 and 7 which
show,
respectively, bottom and top views of the foot spreader module 14 and head
spreader
module 16 against the lower and upper storage layer units 32.
Clips 60, 62 of the kind shown in Figures 8(a) and 8(b) may be used for the
securing of the spreader modules 14, 16 to the adjacent storage layer units 32
in this way.
The longer clip 60 shown in Figure 8(a) may be used where a larger separation
exists
between the ribs 52 of the head spreader module 16 and the framework 54 of the
adjacent
storage layer unit 32. In practice, owing to the positioning of the framework
54 within the
storage layer units 32, the longer clip 60 will be used for the, head spreader
module 16 (see
Figure 7), and the shorter clip 62 will be used for the foot spreader module
14 (see Figure
6).
By virtue of the geometry of the spreader modules 14, 16, and specifically the
presence of 8 ribs 52 which align with corresponding framework of an adjacent
storage
layer unit 32, up to 8 (and preferably at least 2) clips 60, 62 are used for
each spreader
module 14, 16.
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With reference to the clips themselves, each clip 60, 62 has a barbed end 64
for
connecting to an aperture to be formed in a rib 52 of the spreader module 14,
16, and a
hooked end 66 for hooking around an adjacent framework element 54 of the upper
and/or
lower storage layer unit.
Figure 9 shows a pair of adjacent storage layer units 32 coupled together by a
clip
68 which is hooked at both ends. The storage layer units 32 may be coupled
together in
this manner to stabilise the support system 28 during construction.
The above support structure, and support system including the support
structure,
have been described by way of example only and modifications are possible
within the
scope of the invention.
The reference in this specification to any prior publication (or information
derived
from it), or to any matter which is known, is not, and should not be taken as
an
acknowledgment or admission or any form of suggestion that that prior
publication (or
information derived from it) or known matter forms part of the common general
knowledge in the field of endeavour to which this specification relates.
Throughout this specification and the claims which follow, unless the context
requires otherwise, the word "comprise", and variations such as "comprises"
and
"comprising", will be understood to imply the inclusion of a stated integer or
step or group
of integers or steps but not the exclusion of any other integer or step or
group of integers or
steps.
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